Zip fastener construction

ABSTRACT

A zip fastener construction is provided with a stiffening or holding core member extending longitudinally through a row of interlocking elements in the form of a spring coil, said core being securely retained in place against displacement particularly in the transverse direction. The coil element is provided with a space between its arm portions, which space is reduced immediately adjacent the core to hold the latter in abutting engagement with the inner wall of a base portion of the element.

United States Patent [191 Fujisaki 1 Dec. 24, 1974 ZIP FASTENER CONSTRUCTION [75] Inventor: Yoshinori Fujisaki, Kurobe, Japan [73] Assignee: Yoshida Kogyo Kahushiki Kaisha,

Tokyo, Japan [22] Filed: July 26, 1972 [21] Appl. No.: 275,188

[30] Foreign Application Priority Data July 31, 1971 Japan 46-68372 [52] US. Cl. 24/205.l C, 24/205.16 C, 24/205.13 C

[51] Int. Cl A44b 19/12 [58] Field of Search24/205.1 C, 205.13 C, 205.16 C

[56] References Cited UNITED STATES PATENTS 3,149,388 9/1964 Wilcken 24/205.13 C 3,199,162 8/1965 Sohr 24/205.l3 C 3,430,304 3/1969 Swainson I 24/205.1 C 3,491,413 1/1970 Porepp 24/205.16 C

FOREIGN PATENTS OR APPLICATIONS 488,423 5/1970 Switzerland 24/205.1 C

6,804,583 10/1968 Netherlands 24/205.1 C 1,940,734 2/1971 Germany 24/2051 C 7,002,254 2/1970 Netherlands... 24/205.1 C 7,005,706 4/1970 Netherlands 24/205.1 C

Primary ExaminerBemard A. Gelak Attorney, Agent,.or Firm-Robert E. Burns; Emmanuel J. Lobato; Bruce L. Adams [5 7] ABSTRACT A zip fastener construction is provided with a stiffening or holding core member extending longitudinally through a row of interlocking elements in the form of a spring coil, said core being securely retained in place against displacement particularly in the transverse direction. The coil element is provided with a space between its arm portions, which space is reduced immediately adjacent the core to hold the latter in abutting engagement with the inner wall of a base portion of the element.

6 Claims, 4 Drawing Figures ZIP FASTENER CONSTRUCTION This invention relates to zip fasteners, more particularly to improvements relating to the construction of a zip fastener of the type comprising interlocking elements in the form of a spring coil or helix.

It is customary to employ a stiffening or holding core for retaining two mating rows of interlocking coil elements against lateral displacement or misalignment and thus maintaining them in the properly aligned position on the respective stringer tapes. Conventional fastener constructions of the type described have employed stiffening cords or braids made of textile materials, which cords or braids are usually inserted longitudinally through the respective rows of coil elements along the base portions thereof. For retaining the cords in position, there have been used threads that run over the elements in intertwined relation to the cords.

However, such conventioned fastener constructions have suffered from the disadvantage that the intertwining threads tend to become loose upon repeated closing and opening operations of the fastener and the textile cords are liable to shrink in contact water as when the fastener is washed with the results that the cords shift away from the base portions of. the elements, causing irregularities in the pitch angle or alignment of individual convolutions in the rows of interlocking elements and finally the fastener becomes inoperative.

Whereas, it is the primary object of the present invention to provide an improved zip fastener construction which ensures that the interlocking elements are securely held in the properly aligned position on the respective stringers of the fastener and which will overcome the aforesaid disadvantage of the conventional fasteners.

Other objects and features of the invention will appear clear from the following detailed description of certain preferred embodiments taken with reference to the accompanying drawings wherein like reference numerals refer to like parts and wherein:

FIG. 1 is a transverse sectional view on enlarged scale of a first embodiment of the invention;

FIG. 2 is a similar view of a second embodiment;

FIG. 3 is a similar view of a third embodiment; and

FIG. 4 is a similar view of a fourth embodiment.

In order to achieve the above object of the invention, there is provided a zip fastener construction comprising a pair of stringers, mating rows of interlocking elements in the form of a spring coil mounted along the respective inner longitudinal edges of said stringers, each of said elements having a coupling head portion, merging arms defining a space therebetween, and a base portion connecting between adjacent elements, and a holding core made of a thermosetting plastic filament and extending longitudinally through each of said mating rows of elements, said core being firmly held in abutting relation to the inner wall of said base portion when the elements are secured by sewing threads to the respective edges of said stringers, with said space reduced at a point immediately adjacent said core to a width smaller than the diameter of said core.

Referring now to the drawings and FIG. 1 in particular, there is shown an important part of one half of two identical element-carrying stringers in a pair constituting a zip fastener or slide fastener embodying the present invention. A stringer in the form of a fabric tape has mounted along its inner longitudinal edge 1 1 a row of interlocking fastener elements or coupling elements 12 in the form of a spring coil which are engageable with corresponding elements on a mating stringer, not shown. For purposes of illustration, one of the individual convolutions in the coil elements is considered. Each elements 12 taken in terms of an individual convolution consists of a coupling head 13 for interlocking engagement with corresponding coupling head on the mating stringer, two merging arms 14, 15 defining therebetween a space 16 for the insertion of a holding core later described, and a base portion 17 connecting between adjacent elements. lmportantly, a holding or stiffening core 18 employed in accordance with the invention consists of a thermosetting plastic filament such as of polyester, polyamide or the like. The core 18 preferrably round in cross section extends longitudinally through the space 16 adjacent the inner wall 19 of the base portion 17 all way along the row of interlocking elements 12. Being thermosetting, the filament core member when heated for instance during the dyeing of the fastener becomes hardened and set in intimate contact with the inner wall 19 of the base portion 17 of the element 12 thereby holding the row of continuous coil elements 12 properly aligned particularly at the base portions 17 thereof against irregular displacement. The elements 12 are secured into position on the stringer 10 along the inner edge thereof by means of sewing threads 20 as shown. The holding core 18 is retained securely in place by reducing the space or gap 16 at a point 16 immediately adjacent the core 18 to a width smaller than the diameter of the core 18 in a manner that the core 18 is firmly held in abutting relation to the inner wall 19 of the base portion 17 of the element 12. This is achieved by providing a recess 21 in one or upper arm 14 of the element 12 whereby the arm 14 is allowed to bend inwardly relative to the lower arm 15 under the influence of tightening pressure of the sewing threads 20, thus narrowing down the space or gap 16 and forcing the core 18 into abutting engagement with the inner wall 19 of the base portion 17.

The inventive concept discussed above is also implemented by the modified embodiments that are shown in FIGS. 2 4 inclusive.

In the second embodiment shown in FIG. 2, the two arms 14, 15 are bent or flexed inwardly towards each other thereby reducing the space 16 as at 16' under the influence of pressure of sewing threads 20 in a manner already described to retain the core 18 in position.

The third embodiment shown in FIG. 3 is characterized by the provision of an interlocking element having arms 14, 15 provided with inwardly projecting portions 14a, 15a defining therebetween a reduced space 16'.

The fourth embodiment shown in FIG. 4 is characterized by the provision of a space or gap 16 defined between the arms 14, 15, which space progressively converges towards the coupling head 13 of the element 12.

It is to be noted that all of the various embodiments described and illustrated commonly employ a stiffening or holding core 18 which is made of a thermosetting plastic filament in lieu of conventional textile materials. This advantageously ensures that the core 18 retain stability in respect of its shape and position when the fastener is heated during the dyeing or other finishing treatment of the fastener as in the usual practice and it is thus free from changes in the effect of environmental conditions.

Having thus described the invention, it will be understood that the invention is not to be limitted to the precise form and construction herein above advanced, but various changes and modifications may be made therein without departing from the scope of the appended claims.

What is claimed is:

1. In a slide fastener,

21. a stringer;

b. a row of coupling elements comprising, a plurality of coupling elements each having a coupling head and a pair of arms extending from said coupling head in a common direction transverse to a longitudinal direction of said row of coupling elements and defining a space therebetween, and a plurality of base portions connecting next adjacent coupling elements at ends of said arms remote from said coupling heads, one of said arms of each of said coupling elements having an inwardly bulging portion to define a narrow region more narrow than a portion adjacent said base portions of each of the spaces between each of said pair of arms;

c. an elongated core having a transverse width greater than the narrow regions of the spaces between said pairs of arms, said core being disposed in and solely at one end of each of said spaces between each of said pair of arms adjacent said base portions and maintained engaged with said base portions by said bulging portions of said pairs of arms to maintain alignment between said coupling elements; and

d. threads securing said coupling elements to said stringers.

2. In a slide fastener according to claim 1, wherein one of said arms of each of said pairs of arms is flexible, and wherein said threads comprise means inwardly flexing said flexibie arms of each of said pairs of arms to form said inwardly bulging portions defining the narrow region of the space between each of said pair of arms.

3. In a slide fastener according to claim 2, wherein the other of said arms of each of said pairs of arms is flexible, and said threads comprise means inwardly flexing both flexible arms of each of said pair of arms.

4. In a slide fastener according to claim 1, wherein onevarm of each of said pair of arms is provided with a recess in a surface opposite said space between said pair of arms, and said threads being received in said recess.

5. In a slide fastener according to claim 1, wherein both arms of said pairs of arms are provided with an inwardly bulging portion to define the narrow region of the space between each of said pair of arms 6. In a slide fastener according to claim I, wherein said core is made of thermosetting plastic. 

1. In a slide fastener, a. a stringer; b. a row of coupling elements comprising, a plurality of coupling elements each having a coupling head and a pair of arms extending from said coupling head in a common direction transverse to a longitudinal direction of said row of coupling elements and defining a space therebetween, and a plurality of base portions connecting next adjacent coupling elements at ends of said arms remote from said coupling heads, one of said arms of each of said coupling elements having an inwardly bulging portion to define a narrow region more narrow than a portion adjacent said base portions of each of the spaces between each of said pair of arms; c. an elongated core having a transverse width greater than the narrow regions of the spaces between said pairs of arms, said core being disposed in and solely at one end of each of said spaces between each of said pair of arms adjacent said base portions and maintained engaged with said base portions by said bulging portions of said pairs of arms to maintain alignment between said coupling elements; and d. threads securing said coupling elements to said stringers.
 2. In a slide fastener according to claim 1, wherein one of said arms of each of said pairs of arms is flexible, and wherein said threads comprise means inwardly flexing said flexible arms of each of said pairs of arms to form said inwardly bulging portions defining the narrow region of the space between each of said pair of arms.
 3. In a slide fastener according to claim 2, wherein the other of said arms of each of said pairs of arms is flexible, and said threads comprise means inwardly flexing both flexible arms of each of said pair of arms.
 4. In a slide fastener according to claim 1, wherein one arm of each of said pair of arms is provided with a recess in a surface opposite said space between said pair of arms, and said threads being received in said recess.
 5. In a slide fastener according to claim 1, wherein both arms of said pairs of arms are provided with an inwardly bulging portion to define the narrow region of the space between each of said pair of arms.
 6. In a slide fastener according to claim 1, wherein said core is made of thermosetting plastic. 